JP2800203B2 - Electrolyte circulation type secondary battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulating electrolyte secondary battery, and more particularly to a circulating electrolyte secondary battery capable of detecting a leaking electrolyte. is there.

[Prior Art] A conventional technique will be described using a redox flow battery which is a kind of an electrolyte circulation type secondary battery.

FIG. 6 is a schematic configuration diagram of a conventionally proposed redox flow type secondary battery. The redox flow battery includes a cell 1, a positive electrode solution tank 6, and a negative electrode solution tank 5. The inside of the cell 1 is partitioned by a diaphragm 2 made of, for example, an ion exchange membrane, and one side constitutes a positive electrode cell 1a and the other side constitutes a negative electrode cell 2b. In the positive electrode cell 1a and the negative electrode cell 1b, a positive electrode 4 or a negative electrode 3 is provided as an electrode, respectively.

The positive electrode cell 1a is provided with a positive electrode electrolyte introduction pipe 30 for introducing a positive electrode electrolyte. Further, the positive electrode cell 1a is provided with a positive electrode electrolyte outflow tube 31 for discharging the positive electrode electrolyte contained in the positive electrode cell 1a. One end of the positive electrode electrolyte inlet tube 30 and one end of the positive electrode electrolyte outlet tube 31 are connected to the positive electrode tank 6.

The negative electrode cell 1b is provided with a negative electrode electrolyte introduction tube 32 for introducing a negative electrode electrolyte. Also, the negative electrode cell 1b
Is provided with a negative electrode electrolyte outflow pipe 33 for discharging the negative electrode electrolyte contained in the negative electrode cell 1b. One end of the negative electrode electrolyte introduction pipe 32 and one end of the negative electrode electrolyte discharge pipe 33 are connected to the negative electrode liquid tank 5.

In the redox flow battery shown in FIG. 6, for example, an aqueous solution of an ion whose valence changes, such as iron ion or chromium ion, is stored in the positive electrode solution tank 6 and the negative electrode solution tank 5 and the pump P ₁ and the pump P _The liquid is sent to the cell 1 by _{2 and} charge and discharge are performed by an oxidation-reduction reaction.

For example, when Fe ³⁺ / Fe ²⁺ is used as the positive electrode active material and Cr ²⁺ / Cr ³⁺ is used as the negative electrode active material, and the respective hydrochloric acid solutions are used, the battery reactions at both the electrodes 3 and 4 of each redox system are as follows. It becomes like the following formula.

The electrochemical reaction of the above formula yields about 1 volt of power.

By the way, in order to increase the generated voltage of a redox flow battery, a multi-stage connection type redox flow battery in which a plurality of cells are connected in series has been proposed. In FIG.
FIG. 1 is an exploded perspective view showing a cell structure of a cell-type redox flow battery.

Referring to FIG. 7, in cell 1, the components of bipolar plate 15, negative electrode plate 13, diaphragm 12, positive electrode plate 14, and bipolar plate 16 are arranged in order from the left in the figure. The multi-stage connection type is formed by stacking a large number of cells 1, that is, a bipolar plate 15, a negative electrode plate 13,
A large number of components including a diaphragm 12, a positive electrode plate 14, and a bipolar plate 16 are stacked, and both ends thereof are gripped by a terminal plate 17 and a terminal plate 18. A stack of many cells 1 is called cell staff. The bipolar plate 15 includes a bipolar plate frame 15f, the negative plate 13 includes a negative plate frame 13f, and the positive plate 14
Has a positive electrode plate frame 14f, and the bipolar plate 16 has a bipolar plate frame 16f. The bipolar plate frame 15f, the negative electrode plate frame 13f, the diaphragm 12, the positive electrode plate frame f, and the bipolar plate frame 16f are provided with through holes, and manifolds 20, 21, 22, and 23 serving as internal piping are connected. Have been.

In the bipolar plate frame 15f, a slit 15a for supplying a positive electrode solution,
Slit 15b for feeding the positive electrode solution, slit 15c for supplying the negative electrode solution,
A slit 15d for delivering a negative electrode solution is provided and connected to the manifold 21, the manifold 23, the manifold 20, and the manifold 22, respectively.

In the bipolar plate frame 16f, a slit 16a for supplying a positive electrode solution,
A slit 16b for delivering the positive electrode, a slit 16c for supplying the negative electrode solution, and a slit 16d for sending the negative electrode solution are provided and connected to the manifold 21, the manifold 23, the manifold 20, and the manifold 22, respectively. Among the many bipolar plates 16 existing in the cell staff, the negative electrode solution supply slit 16c and the negative electrode solution delivery slit 16d provided on the bipolar plate frame 16f of the bipolar plate 16 in contact with the terminal plate 18 are closed. Also, of the large number of bipolar plates 15 existing in the cell staff, a bipolar plate frame 15f of the bipolar plate 15 in contact with the terminal plate 17
The slit 15a for supplying the positive electrode solution and the slit 15b for supplying the positive electrode solution, which are provided in the above, are closed.

At the time of charge / discharge operation, the cathode electrolyte passes through the manifold 21 and is supplied into the inside of the cathode cell 1a from the cathode solution supply slit 16a. Sent to 23. Further, the negative electrode electrolyte is supplied to the inside of the negative electrode cell 1b from the negative electrode liquid supply slit 15c through the manifold 20, and after being charged and discharged by the negative electrode reaction electrode 13e, is sent out to the manifold 22 from the negative electrode liquid supply slit 15d. You. At this time, both terminal boards 1
A current flows between 7, 18 and a voltage is generated, and the current is extracted.

Incidentally, use with reference to FIG. 6, the tank (negative electrolyte tank 5, the cathode solution tank 6), the pump (pump P _2, the pump P _1), a pipe connecting the respective cell stacks, a material resistant to the electrolyte It consists of a pipe, a flange, a sealing material and the like.

[Problem to be Solved by the Invention] A conventional redox flow battery is configured as described above. However, the terminal plates 17 and 1 at the end of the cell stack
Cracks or cracks may occur on the bipolar plates 15 and 16 in contact with 8 for some reason. Cracks on bipolar plates 15, 16
When the crack occurs, the electrolyte leaks and comes into contact with the terminal plates 17 and 18. Here, terminal plates 17 and 18 are bipolar plates 15 and 16
And a cushion material (not shown) such as a rubber sheet, and the terminal plates 17 and 18 and the bipolar plates 15 and 16 are sealed. Therefore, the leaked electrolyte in contact with the terminal plates 17 and 18 returns to the electrode side. By the way, since the terminal plate is generally formed of a plate of copper, aluminum, or the like or a mesh (based on wires), when the terminal plate comes into contact with a leaking electrolyte solution (formed of hydrochloric acid, etc.), the copper, aluminum, etc. Dissolves in electrolyte. When the leaked electrolytic solution in which the metal such as copper and aluminum is dissolved returns to the electrode side as described above,
In addition to causing a decrease in charge / discharge efficiency, these metals act as catalysts to cause decomposition of the electrolytic solution, which is a problem. Further, there has been a problem that the terminal plates 17 and 18 are corroded by the electrolytic solution, and in some cases, the terminal plates are partially melted and stopped.

Either problem is caused by the fact that the bipolar plate is broken and the leakage of the electrolyte is not visible from the outside of the cell staff and is not noticed.

The present invention has been made in order to solve the above problems, and provides an electrolyte circulation type secondary battery capable of detecting leakage of an electrolyte caused by a crack, a crack, or the like of a bipolar plate. The purpose is to:

[Means for Solving the Problems] The present invention includes a bipolar plate having an outer frame, a cell stack in which electrodes for performing a battery reaction and a diaphragm are alternately laminated, and a terminal plate in contact with the bipolar plate. The present invention relates to an electrolyte circulation type secondary battery. In order to solve the above problem, the electrolyte circulating secondary battery is configured such that the electrolyte leaking between the bipolar plate and the terminal plate due to cracks, cracks or the like of the bipolar plate is stacked in a cell stack. And a leakage electrolyte detection means for detecting the leakage electrolyte taken out from the extraction means.

Further, according to a preferred aspect of the present invention, the leaked electrolyte detecting means may be arranged so as to be able to detect all the leaked electrolyte leaking from any part of the electrolyte circulation type secondary battery. .

[Operation] As described above, the electrolyte circulation type secondary battery according to the present invention takes out the electrolyte leaking between the bipolar plate and the terminal plate to the outside of the cell stack due to cracking, cracking, or the like of the bipolar plate. And a leaking electrolyte detecting means for detecting the leaking electrolyte taken out from the taking out means, so that cracks or cracks in the bipolar plate cause leakage between the bipolar plate and the terminal plate. The incoming electrolyte is taken out without returning to the electrode side, and is detected by the leaked electrolyte detection means.

Further, when the leaked electrolyte detecting means is arranged so as to be able to detect all the leaked electrolyte leaking in any part of the electrolyte circulation type secondary battery, not only leakage of the electrolyte in the bipolar plate portion, An electrolyte leak in the entire apparatus can be found at an early stage, and countermeasures can be taken.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a cell stack of the electrolyte circulation type secondary battery according to the present invention. FIG. 2 is an enlarged view of a portion A in FIG. In FIG. 2,
The terminal plate 18 is illustrated as being pressed against the bipolar plate 16.

The embodiment shown in FIG. 1 is the same as the conventional example shown in FIG. 7 except for the following points, and the corresponding parts are denoted by the same reference numerals and description thereof will be omitted.

The difference between the embodiment shown in FIG. 1 and the conventional example shown in FIG. 7 is that the electrolytic solution leaking out due to cracks, cracks or the like of the bipolar plate 15 is taken out to the bipolar plate frame 15f of the bipolar plate 15. Slit 15s is provided, and on the bipolar plate frame 16f of the bipolar plate 16, a slit which is an extraction means for extracting an electrolyte leaking out due to cracks, cracks, etc. of the bipolar plate 16 is provided.
16s is provided. As shown in FIG. 2, it is more preferable to attach a small-diameter pipe to the slit 16s,
This is not essential.

When such a slit is provided, even if the bipolar plate 16 is damaged by cracks, cracks, etc., and the electrolyte leaks, the leaked electrolyte is taken out through the slit 16s through the pipe 16p. By detecting the electrolyte taken out by the electrolyte detection means, cracks and cracks of the bipolar plate can be found at an early stage.

FIG. 3 is a schematic diagram of an electrolyte circulation type secondary battery provided with a leakage electrolyte detection means for detecting a leakage electrolyte taken out through a slit 16s and a pipe 16b. The leaked electrolyte detection means 35 includes a liquid reservoir 36 provided below the electrolyte circulation type secondary battery, and a leaked electrolyte detection sensor 37 provided in the liquid reservoir 36.

Referring to FIGS. 2 and 3, the electrolyte leaked due to cracks, cracks and the like of bipolar plate 16 is stored in liquid reservoir 36 through slit 16s and pipe 16b arranged in slit 16s. The electrolyte stored in the liquid reservoir 36 is detected by a leak electrolyte detection sensor 37. Thereby, cracks and cracks of the bipolar plate can be found at an early stage. Also, the reservoir
By disposing 36 in the entire lower part of the electrolyte circulation type secondary battery, all the leaked electrolyte leaking from any part of the secondary battery is stored in the reservoir 36 and detected by the leaked electrolyte detection sensor 37. Will be done. As a result, not only the electrolyte leakage in the terminal plate portion but also the electrolyte leakage of the entire device can be found at an early stage, and a countermeasure can be taken.

FIG. 4 is a conceptual diagram of another embodiment of the electrolyte circulation type secondary battery in which the leak electrolyte detection sensor is arranged.

In the embodiment shown in FIG. 4, the liquid electrolyte is not used and the leaked electrolyte detection sensor 37 is connected to the upper end and lower end of the cell 1, the upper end, the side and the lower end of the negative electrode tank 5, and the positive electrode tank 6 At the upper end, side and lower end.
Even with such a configuration, it becomes possible to detect all of the electrolyte leakage in the terminal plate portion and the electrolytic leakage in any other portion of the device. As a result, leakage of the electrolyte can be found at an early stage, and a countermeasure can be easily taken.

FIG. 5A is a perspective view of a leaked electrolyte detection sensor employed by the present invention. The leakage electrolyte detection sensor 37 is a conducting wire
37a and an insulator 37b covering the conductor 37a.
The insulator 37b has a property of absorbing the electrolytic solution. When the leaked electrolysis is absorbed by the insulator 37b, the insulator 3
7b becomes conductive, a current flows between the conductive wires 37a, 37a, and leakage of the electrolyte is detected.

FIG. 5B is a perspective view of another embodiment of the leaked electrolyte detection sensor used in the present invention. Leakage electrolyte detection sensor 37
Consists of two conductors 37a, 37a and an insulator 37b for fixing the two conductors 37a, 37a. This leaked electrolyte detection sensor is used with the conducting wires 37a, 37a exposed. When the electrolyte 38 comes into contact with this sensor, the two conducting wires 37a, 37a
The connection is conducted, current flows, and leakage of the electrolyte is detected.

FIG. 5C is a perspective view of still another embodiment of the leaked electrolyte detection sensor employed in the present invention. The leaked electrolyte detection sensor includes two conductors 37a and an insulator 37b surrounding the conductors 37a. The insulator 37b is provided with openings for exposing the conductive wires 37a, 37a in places. When the electrolytic solution 38 comes into contact with the opening where the conductive wires 37a, 37a are exposed, the conductive wires 37a, 37a are conducted, current flows, and leakage of the electrolytic solution is detected.

As described above, the electrolyte circulation type secondary battery of the present invention has been described with reference to the specific examples. However, the present invention may be implemented in various other forms without departing from the spirit or main characteristics. Can be. Therefore, the above-described embodiments are merely illustrative in all respects and should not be construed as limiting. The scope of the present invention is defined by the appended claims, and is not limited by the text of the specification. further,
All modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

[Effects of the Invention] As described above, according to the electrolyte circulation type secondary battery of the present invention, the electrolytic solution is provided on the outer frame of the bipolar plate at both ends and leaks due to cracks, cracks, and the like of the bipolar plate. Since there are provided a take-out means for taking out the liquid to the outside and a leaked electrolyte detection means for detecting the leaked electrolyte taken out from the take-out means, cracks, cracks, etc. occur in the bipolar plate, and the electrolyte leaks. However, since the electrolyte is taken out and detected, cracks and cracks in the bipolar plate can be found at an early stage.

When the leaked electrolyte detecting means is arranged so as to be able to detect all the leaked electrolyte leaking from any part of the device, not only the electrolyte leak at the terminal plate portion but also any of the devices in the device is not limited. Since all of the electrolyte can be detected by leaking at such a portion, the electrolyte leak of the apparatus can be detected at an early stage, and countermeasures can be taken.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a cell stack according to the present invention. FIG. 2 is an enlarged perspective view of a portion A in FIG. FIG. 3 is a conceptual diagram of an electrolyte circulation type secondary battery provided with a leakage electrolyte detection means according to the present invention. FIG. 4 is a perspective view of another embodiment of the electrolyte circulation type secondary battery provided with the leak electrolyte detection means. 5A, 5B, and 5C,
FIG. 2 is a perspective view of a leakage electrolyte detection sensor employed in the present invention. FIG. 6 is a schematic view of a conventionally proposed redox flow secondary battery. FIG. 7 is an exploded perspective view of a conventional cell stack. In the figure, 1 is a cell, 12 is a diaphragm, 13 is a negative electrode plate, 14 is a positive electrode plate, 15 is a bipolar plate, 15f is an outer frame of the bipolar plate, 15s is a slit provided in the outer frame, 16 is a bipolar plate, 16f Is the outer frame of the bipolar plate, 1
6s is a slit provided in the outer frame, 16p is a pipe arranged in the slit, 17 and 18 are terminal plates, 37 is a leak electrolyte detection sensor, and 38 is a leak electrolyte. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. An electrolyte circulation type secondary battery comprising: a bipolar plate having an outer frame; a cell stack in which electrodes and a diaphragm for performing a battery reaction are alternately laminated; and a terminal plate in contact with said bipolar plate. A means for taking out an electrolyte leaking between the bipolar plate and the terminal plate due to a crack, a crack, or the like of the bipolar plate to the outside of the cell stack; and the leakage taken out from the taking out means. An electrolyte circulation type secondary battery, comprising: a leakage electrolyte detection means for detecting an electrolyte. 2. The leaked electrolyte detecting means is arranged so as to detect all leaked electrolyte leaking from any part of the electrolyte circulation type secondary battery.
Item 2. The electrolyte circulation type secondary battery according to Item 1.